Neuromuscular Adaptations and Dynamic Postural Stability According to Isometric Contraction Duration in Soccer Players with Chronic Ankle Instability: A Randomized Pilot Study
Year: 2026
Type: article
Study design: Clinical Trial
Abstract: Background: Chronic ankle instability (CAI) is a common functional impairment in soccer players that compromises physical power, rate of force development, and dynamic balance.Isometric training is an effective rehabilitation modality, but how specific contraction hold durations modulate distinct neuromuscular adaptations and joint stability outcomes remains unclear.Objective: To compare the effects of 8-week isometric training with different contraction hold durations (3 seconds vs. 5 seconds) on isometric strength, lower-limb power, and dynamic postural stability in soccer players with CAI.Methods: Twenty-eight male collegiate soccer players with CAI (age: 20.4 ± 1.2 years) were randomized into either a 3-second isometric training group (3s-ITG, n = 14) or a 5-second isometric training group (5s-ITG, n = 14).Both groups performed progressive lower-limb isometric training 3 times per week for 8 weeks with equalized cumulative contraction volume per session.Isometric Mid-Thigh Pull (IMTP) peak force and rate of force development (RFD), Countermovement Jump (CMJ) height and max rebound contact time, and dynamic landing contact time and time to stabilization (TTS) on dual force plates were assessed at pre-and post-intervention.Results: Both groups showed significant improvements in all outcome measures over time (p < .05).However, distinct group-by-time interactions were observed.The 5s-ITG showed a significantly greater increase in Peak Force (+20.2% vs. +11.1%;p = .021)and a greater reduction in TTS (-23.3% vs. -14.6%;p = .035)than the 3s-ITG.Conversely, the 3s-ITG achieved significantly greater improvements in RFD (+21.0% vs. +16.7%;p = .023),Jump Height (+16.2% vs. +7.9%;p = .039),and dynamic landing Contact Time (-12.7% vs. -8.9%;p = .029)compared to the 5s-ITG.Conclusion: Both protocols effectively enhance neuromuscular function in soccer players with CAI.However, a 5-second contraction hold is superior for maximizing absolute force capacity and dynamic joint stabilization, whereas a 3-second contraction hold is highly recommended for optimizing rapid explosive power, stretchshortening cycle efficiency, and dynamic landing speed.
Author: JaeHo Yu
Institution: Sun Moon University
Language: English
Topic: Foot and Ankle Surgery
Subfield: Orthopedics and Sports Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W7171318656